Curiosity — the car-sized remote vehicle with an array of sophisticated instruments — may have travelled only a little more than 1.6 km within the Gale Crater on Mars as it completed >one year on the red planet August 6, but the invaluable information it has sent back has certainly changed our understanding of the planet. In all, it has so far transmitted more than 190 gigabits of data and about 37,000 full images. The breathtaking discoveries started well before it soft-landed on Mars; for the first time ever, it became known that astronauts travelling to Mars on a round trip would be exposed to a “hefty dose of damaging radiation” that is close to the lifetime limit. The wealth of information it returned fulfilled the mission’s prime objective — to know if Mars ever had a habitable environment. The presence of paleowater had to be established to prove habitability. Its discovery of a “higher than anticipated” amount of water bound to sand grains in the soil sample came first. Curiosity then provided conclusive evidence that not just water, but drinkable water once existed. This was when the rover became the first to ever drill into rock on another planet. The powered mudstone sample analysed on board confirmed the presence of clay — it forms when water is neither acidic nor alkaline. Gypsum veins confirmed that water once flowed through fractures, even if the quantum of water present is not known. The presence of sedimentary rocks provided more information. But the discovery of a dry river bed with rock layers containing rounded pebbles was a bonanza. The rounded nature of the pebbles revealed many facets of the river, including the depth and speed of water flow and the length of the water course.
NASA announced in December last year the launch in 2020 of a Curiosity clone. But the mission’s goals are bound to go up many notches in the light of our changed understanding of the red planet’s environment a few billion years ago. If instruments to look for signs of life that once existed were already factored in, the array of instruments to be carried and the complexity of measurement to be made are surely bound to be upgraded. Whether the agency would wait for a future mission to bring back samples remains to be seen. Aside from the unimaginable palaeo-environmental findings by the rover since February, the radiation dose data collected by it during its long journey would mean that manned missions to Mars may not be possible in the immediate future. The agency has to go back to the drawing board to build a better spacecraft and protection gear for astronauts when they are on Mars for a year and outside the spacecraft conducting experiments for even very brief periods.